1. Field of the Invention
The invention relates to a method and an apparatus for controlling communication between a terminal and a number of chip cards.
2. Description of the Related Art
German Patent 196 35 311 A1 discloses a method for controlling communication between a terminal and a number of chip cards, in which communication is maintained within a communication range between the terminal on the one hand and the chip cards of different manufacturers or different types on the other. After the signals emitted by the terminal have been decoded in the chip card and compared with characteristic information stored in the chip card, it can be determined whether the chip card corresponds to a certain signal frequency. Thus, groups of different type chip cards can be formed whose communication with the terminal can take place without interference from cards of another type.
With the prior art, however, communication with individual cards is not addressed. The invention is addressed to the problem of devising a method of and an apparatus for controlling communication between a terminal and a number of chip cards such that secure and rapid communication is assured between the terminal and the individual chip cards.
For the solution of this problem, a method according to the invention comprises the steps of: emitting electromagnetic waves by a terminal to form a communication zone for communication between the terminal and at least one of a plurality of chip cards; transmitting an answer-to-reset by one of the plurality of chip cards; generating an identifier by the terminal corresponding to the one chip card; and storing the identifier in the terminal.
In one embodiment, the identifier may be transmitted to the one chip card and stored therein. The identifier may be transmitted in an initial part of a communication between the terminal and the one chip card. The identifier may be deleted in an end part of a communication between the terminal and the one chip card with an end command emitted by the terminal.
An apparatus according to the invention comprises a terminal generating an electromagnetic field to form a communication zone and a plurality of chip cards arranged in the communication zone of the terminal. An identifier is generated and is stored in at least one of the terminal and one chip card from the plurality of chip cards, for identification of the one chip card.
The identifier may be in the form of a terminal-specific identification word. The identifier may be stored in a RAM memory of the chip card.
A different identifier may be assigned to each of a plurality of chip cards entering the communication zone. The different identifiers are generated according to the order of entry of a chip card into the communication zone.
Identifiers for a plurality of chip cards may be stored in an identification file of a memory of the terminal. A sequence of the identifiers is in the form of a dynamic order of identification, such that a storage location of an identifier corresponding to a particular chip card is overwritten in the memory of the terminal after communication between the terminal and the chip card.